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Your search keyword '"Min, Run"' showing total 40 results
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40 results on '"Min, Run"'

2. Sample Voltage Dead-Beat Control Based on Differentiative Voltage Prediction and Switching-Cycle Extension for DC-DC Converters.

Author

Li, Qidong, Zhang, Desheng, Zhu, Liying, Zhang, Wenjia, Min, Run, Zhang, Qiao, and Tong, Qiaoling

Subjects
DC-to-DC converters, VOLTAGE control, PULSE width modulation, VOLTAGE
Abstract

In this paper, a sample voltage dead-beat control based on differentiative voltage prediction (DVP) and switching-cycle extension (SCE) is presented to achieve optimal transient response for DC-DC converters under discontinuous conduction mode (DCM) operation. Firstly, to improve load transient response, a DVP method is proposed to estimate the load. With the estimated load, the controller realizes load current feedforward and thus improves the transient response with a wide load range. Secondly, an SCE strategy is proposed to enlarge the output current range and output voltage slew rate, both of which have limited value under conventional digital pulse width modulation (DPWM). When the output current reaches the limited value, the proposed strategy increases the switching cycle to enlarge the current range without losing DCM operation. Finally, combining DVP with SCE, the converter not only achieves optimal response in large signal transients, but also doubles the load range in DCM operation. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Optimal Duty Ratio Assisted PFM Control for VHF Isolated Class E DC-DC Converter

Author

Zhang, Desheng, Lu, Liangliang, Song, Wei, Min, Run, Tong, Qiaoling, Zhang, Qiao, Peng, Han, and Zhou, Keliang

Abstract

This article presents an optimal duty ratio assisted pulse frequency modulation control for very high frequency isolated class E dc–dc converter to achieve both continuous power flow and optimal switch timing. The continuous power flow significantly reduces output ripple of the converter, while the optimal switch timing guarantees consistent zero-voltage-switching (ZVS) and minimized reverse conduction loss. To pave the way for the proposed control, a resonant fitting model is established for deriving the optimal duty ratio and output power under dynamic switching frequency. The optimal duty ratio is calculated according to zero-crossing points of the switching node voltage (vds), and it aims to turn on the power switch once vds reaches zero. This ensures consistent ZVS while preventing reverse conduction of gallium nitride (GaN) high electron mobility transistor (HEMT) when the switching frequency changes. Furthermore, the proposed control is integrated with on/off modulation to extend load range of the converter. A 10–18 MHz prototype is built to verify effectiveness of the proposed control. Compared with conventional PFM control, the proposed control reduces the power loss by 35.9% at 40% load while maintains continuous power flow.

Published
2023
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12. Online Inductance and Capacitance Identification Based on Variable Forgetting Factor Recursive Least-Squares Algorithm for Boost Converter

Author

Chen Chen, Min Run, Tong Qiaoling, Tao Shifei, Lyu Dian, and Li Linkai

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

The control performance of boost converter suffers from the variations of important component parameters, such as inductance and capacitance. In this paper, an online inductance and capacitance identification based on variable forgetting factor recursive least-squares (VFF-RLS) algorithm for boost converter is proposed. First, accurate inductance and capacitance identification models and the RLS algorithm are introduced. In order to balance the steady-state identification accuracy and parameter tracking ability, a forgetting factor control technique is investigated. By recovering system noise in the error signal of the algorithm, the value of forgetting factor is dynamically calculated. In addition, since the sampling rate is much lower than the existing identification methods, the proposed algorithm is practical for low-cost applications. Finally, the effectiveness of the proposed algorithm is verified by experiment. The experiment results show that the algorithm has good performance in tracking inductance and capacitance variations.

Published
2018
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14. Reducing Circling Currents in a VHF Class Φ 2 Inverter Based on a Fully Analytical Loss Model.

Author

Zhang, Desheng, Min, Run, Liu, Zhigang, Tong, Qiaoling, Zhang, Qiao, Wu, Ting, Zhang, Ming, and Zhou, Aosong

Subjects
*ROOT-mean-squares, *IDEAL sources (Electric circuits)
Abstract

This paper proposes a fully analytical loss model to reduce circling currents and improve the power efficiency of a class Φ2 inverter. Firstly, analytical expression of the switching node voltage is derived by analyzing its harmonic components. Based on the result, the power switch is modeled as a voltage source, where the circuit is simplified to a linear network and analytical expressions of branch currents are solved. Secondly, root mean square (RMS) values of branch currents and component losses are calculated to form the analytical loss model for a Φ2 inverter. The influence of circuit parameters on the circling current and power efficiency are thoroughly analyzed, which derives optimal design constraints to reduce circling currents of a class Φ2 inverter. Furthermore, detailed design guidance and equations are provided to calculate circuit parameters of a class Φ2 inverter, which reduces its circling currents and improves overall power efficiency. Finally, a class Φ2 inverter prototype is built, and experimental results demonstrate a 7% efficiency improvement compared to conventional empirical design methods. [ABSTRACT FROM AUTHOR]

Published
2022
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15. Harmonic Weighting and Target Function Design Strategy to Minimize Switch Voltage Stress of Class Φ 2 Inverter.

Author

Zhang, Desheng, Lu, Liangliang, Tong, Qiaoling, Zhang, Qiao, Min, Run, Peng, Han, and Zou, Xuecheng

Subjects
VOLTAGE, IDEAL sources (Electric circuits), HARMONIC distortion (Physics), ELECTROSTATIC induction
Abstract

For very high frequency (VHF) class Φ2 inverter, conventional design method requires complex tuning for parameters. Without fully quantitative calculations, the tuning highly depends on experience that cannot achieve optimal design. In this article, a target function design strategy is proposed based on quantitative harmonic weighting, which simplifies the design procedures and minimizes the switch voltage stress. First, the target switch voltage with minimized peak value is derived by optimizing the harmonic weighting. With the result, the power switch is modeled as a voltage source to simplify the calculations, where the branch currents are solved to provided fully quantitative analysis. Based on the analysis, optimal features of switching node impedance are derived to achieve the target switch voltage. In addition, basic constrains of the resonant tank are analyzed to reduce circling currents. Combining the optimal features and basic constrains of the resonant tank, the circuit parameters are calculated directly, which minimizes the switch voltage stress and improves power efficiency. Compared with conventional design, a 27.12 MHz prototype demonstrates 10.2% reduction in average switch voltage stress and 7.2% improvement in average efficiency. [ABSTRACT FROM AUTHOR]

Published
2022
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